Eagle fish mark 320

I just purchased a new boat and it came with 2 of these. My deal is I don't know anything about them. Are they worth keeping or should I keep my plan of replacing. They are like new. I have one on the column and one up front.

i use a 320 and have no trouble locating fish. but have been around some color units lately and really like the color screen.but i can locate cats and shad pretty easy with it . get to 45 foot of water and it doesnt show the arches as strong, even with the sensitivity turned way up. its great for 45 feet and shallower.